Tham khảo tài liệu 'aerial vehicles part 16', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Autonomous Guidance of UAVs for Real-Time Target Tracking in Adversarial Environments 741 Figure 10. Case 1 UAV trajectory following an accelerating target Figure 11. Case 2 UAV trajectory following a slowing target 742 Aerial Vehicles shows the second case where the target while moving on the path shown in Fig 11 reduces its speed to 36 km h in 600 seconds and then maintains it in the rest of the pursuit. Note that the speed of the target is much less than the minimum speed of the UAV during the most of the pursuit. Thus the UAV reduces its speed to the minimum speed and tries to loiter within the proximity disk when there is no restricted area while minimizing the threat exposure level as shown in . Note that there is no pre-defined loitering mode in algorithm. In fact there is no need for the strategy to have a separate loitering mode because the strategy puts the UAV in loitering autonomously based on the speed of the proximity circle and the local PTEM within the proximity disk. The third case is shown in and 13. In this case target continuously reduces its speed and stops at 660 seconds in a region where there is no restricted area. After staying in this region for 140 seconds the target at 800 seconds starts accelerating and reaches its maximum speed at 1000 seconds. At 1100 seconds it starts decelerating again and stops at 1360 seconds in a restricted region during the rest of the pursuit. This case shows the full capability of the strategy for autonomously putting the UAV in loitering mode both with and without restricted areas close-by. As seen from when the target stops in a region where there is no close-by restricted region the algorithm puts the UAV in loitering around the local minimum of the PTEM inside the proximity circle. This shows the benefit of utilizing the proximity-circle tangent-direction. Also note from that when the target stops the second time within a restricted area a small portion of the proximity
